Use of X-ray Tomography to Map Crystalline and Amorphous Phases in Frozen Biomaterials

The outcome of both cryopreservation and cryosurgical freezing applications is influenced by the concentration and type of the cryoprotective agent (CPA) or the cryodestructive agent (i.e., the chemical adjuvants referred to here as CDA) added prior to freezing. It also depends on the amount and type of crystalline, amorphous and/or eutectic phases formed during freezing which can differentially affect viability. This work describes the use of X-ray computer tomography (CT) for non-invasive, indirect determination of the phase, solute concentration and temperature within biomaterials (CPA, CDA loaded solutions and tissues) by X-ray attenuation before and after freezing. Specifically, this work focuses on establishing the feasibility of CT (100–420 kV acceleration voltage) to accurately measure the concentration of glycerol or salt as model CPA and CDAs in unfrozen solutions and tissues at 20°C, or the phase in frozen solutions and tissue systems at −78.5 and −196°C. The solutions are composed of water with physiological concentrations of NaCl (0.88% wt/wt) and DMEM (Dulbecco’s Modified Eagle’s Medium) with added glycerol (0–8 M). The tissue system is chosen as 3 mm thick porcine liver slices as well as 2 cm diameter cores which were either imaged fresh (3–4 h cold ischemia) or after loading with DMEM based glycerol solutions (0–8 M) for times ranging from hours to 7 days at 4°C. The X-ray attenuation is reported in Hounsfield units (HU), a clinical measurement which normalizes X-ray attenuation values by the difference between those of water and air. NaCl solutions from 0 to 23.3% wt/wt (i.e. water to eutectic concentration) were found to linearly correspond to HU in a range from 0 to 155. At −196°C the variation was from −80 to 95 HU while at −78.5°C all readings were roughly 10 HU lower. At 20°C NaCl and DMEM solutions with 0–8 M glycerol loading show a linear variation from 0 to 145 HU. After freezing to −78.5°C the variation of the NaCl and DMEM solutions is more than twice as large between −90 and +190 HU and was distinctly non-linear above 6 M. After freezing to −196°C the variation of the NaCl and DMEM solutions increased even further to −80 to +225 HU and was distinctly non-linear above 4 M, which after modeling the phase change and crystallization process is shown to correlate with an amorphous phase. In all tissue systems the HU readings were similar to solutions but higher by roughly 30 HU, as well as showing some deviations at 0 M after storage, probably due to tissue swelling. The standard deviations in all measurements were roughly 5 HU or below in all samples. In addition, two practical examples for CT use were demonstrated including: (1) glycerol loading and freezing of tissue cores and, (2) a mock cryosurgical procedure. In the loading experiment CT was able to measure the permeation of the glycerol into the sample at 20°C, as well as the evolution of distinct amorphous vs. crystalline phases after freezing to −196°C. In the mock cryosurgery example, the iceball edge was clearly visualized, and attempts to determine the temperature within the iceball are discussed. An added benefit of this work is that the density of these frozen samples, an essential property in measurement and modeling of thermal processes, was obtained in comparison to ice.     

基于VTK的磁源性影像三维可视化

目的 改善磁源性影像的三维可视化效果.方法 对MRI数据进行图像分割,利用可视化工具(vTK)包对分割后的图像进行三维重建,获得大脑皮层的三维模型;以患者做脑磁图检查时设置的3个外部标志点(左耳窝、右耳窝和鼻根)为基准,通过坐标转换,将脑磁图源分析软件输出的偶极子信息形象化地表示在三维显示窗口中.结果 在三维图像上可以...     

形象化健康教育模式对肠造口患者短期生活质量的影响

目的探讨形象化健康教育模式对肠造口患者自我护理能力及短期生活质量的干预作用。方法采用随机对照方法对我科2008年7月~2009年2月收治的53例直肠癌结肠造口患者随机分为观察组(27例)和对照组(26例)。观察组患者采用形象化健康教育模式,对照组患者采用传统护理方法。使用欧洲癌症研究与治疗组织的生活质量核心量表(EORTC QLQ-C30)V3.0中文版分别对两组病人入院时、出院后3个月的生活质量进行评分。结果观察组患者躯体功能、角色功能、情绪功能、认知功能、社会功能和总体健康状况方面在出院后3个月时均优于对照组,P0.05,差异有显著意义。结论形象化健康教育模式较传统护理方法能快速提高肠造口患者自我护理能力,并能显著改善肠造口患者的短期生活质量。     

The study of three-dimensional reconstruction of Chinese adult liver

Purpose  To build a three-dimensional (3D) visible model of human liver and provide visualization of precise anatomical structures for making plans for hepatic operations and obtain accurate simulation of liver on computer. Methods  Based on the Chinese Visible Human data set, the hepatic structures were precisely segmented by Photoshop software. Then the segmented structures were reconstructed in surface rendering method and the hepatic parenchyma and the other parts of upper abdomen were reconstructed with volume rendering method by using our software on personal computer. Results  A 3D model of human liver and its surrounding structures was built. The reconstructed structures can be displayed singly, in small groups or as a whole and can be continuously rotated in 3D space at different velocities. This model can help doctors to understand the spatial structure of the liver and its surrounding organs and also help surgeons to devise a reasonable surgical plan and reduce the risk of surgical malpractice. Conclusion  Combining volume-rendering reconstruction with surface rendering reconstruction can overcome some of the defects of both rendering reconstructions. The reconstructed liver and the main internal structures are realistic, which demonstrate the natural shape and exact position of the structures. They provide an accurate anatomical model for Chinese adult and also provide a basis for performing virtual hepatic operation.     

Design and test of a PC-based portable three-dimensional ultrasound software system Ultra3D

Currently, portable ultrasound units lack three-dimensional (3D) image display, limiting their potential usefulness especially under remote and hostile operating environments where information must be intuitive and objective. A freehand 3D image processing and visualization software package, Ultra3D, has been developed and tested, especially to work with a miniaturized linear-array transducer probe that is connected to a laptop PC. This paper presents the software design and method to integrate Ultra3D into Terason's miniaturized SmartProbe for freehand 3D ultrasound imaging. Since images generated by Ultra3D are in a digital imaging and communications in medicine (DICOM) format, data sharing with others is easy.     

医学图像可视化及加速技术的研究进展和趋势****☆

摘要：近年来图像可视化技术蓬勃发展,相应的各种加速算法也层出不穷,本文将尝试就此内容进行综述和概括。首先介绍可视化技术的两大分支——面绘制和体绘制的含义和主要特点;其次详细介绍体绘制技术中一些典型算法的基本原理及各自特点;然后分别从软件和硬件角度归纳体绘制技术中常用的加速技术;最后展望医学图像可视化及加速技术的发展趋势。     

计算机辅助医学图像三维重建的算法分析

背景：基于三维重建的医学图像可视化技术具有广阔的应用前景,是目前研究的热点内容。目的：为医学图像三维重建时算法的选择提供帮助。方法：分析面绘制重置方法和体绘制重置方法的实现原理、实现复杂度、实时显示情况等方面。结果与结论：在对重建方法分析的基础上,总结出面绘制和体绘制两种方法各自的优势和弱点,分析在不同情况下如何进行算法的选择。     

交互式医学图像控制系统在正颌外科手术中的应用

目的 探讨交互式医学图像控制系统（MIMICS）在计算机辅助手术中的应用价值,为术前进行精确设计手术方案及达到术后良好效果提供真实可靠依据。方法 对2例正颌外科手术患者的头面部三维CT断层扫描图像,进行识别确定重建对象,对皮肤、皮下组织及骨组织采用灰度阈值法进行自动重建;采用MIMICS软件对获取的医学信息进行分层网格划分,完成建模。根据资深正颁外科医师制订的方案,在模型中完成手术的模拟和软组织形变的预测。结果 完成了包含皮肤、皮下组织和骨组织的患者头面部三维网格模型。模拟了正颌外科手术移动骨质过程,并且以动态动画形式演示,可从任意角度进行观察。实现了正颌外科手术术后软组织形变的可视化预测。结论 利用医学影像资料,采用MIMICS软件可实现人头面部复杂结构的三维重建和分层网格划分,以动态形式完成正颌外科手术的模拟和软组织形变预测。在计算机屏幕前制订手术方案进行医患交流,共同协商,提高了正颌外科手术安全性、精确性和矫治效果。     

Research hotspot and trend of microneedles in biomedical field: A bibliometric analysis from 2011 to 2020

BackgroundMicroneedles composed of arrays of micro-sized needles assembled on a patch, has attracted increasing interest in transdermal drug delivery due to its ease of use and lack of painful responses. Here, a bibliometric analysis was conducted to determine a hotspot and trend of microneedles in the biomedical field.MethodsAll relevant articles about microneedles between 2011 and 2020 were obtained from the databases of Web of Science (WOS) and PubMed of the National Center for Biotechnology Information (NCBI). A series of software such as VOSviwewer, the online bibliometric analysis website, CiteSpace, BICOMB and gCLUTO were used to process the data and get visual images. Processed data and visualized images were conducted to predict the trend of this research field.ResultsThe number of articles published over the last decade had increased rapidly (37 in 2011, 165 in 2020), the Journal of Controlled Release was the most productive journal in microneedle studies. The United States was the most productive country, while the Queens Univ Belfast topped the other institutions. Ryan F Donnelly was the most productive author in the field, while the two most cited articles were published by Gu Zhen group. More importantly, the research trend of microneedles had ranged from physicochemical properties and pharmacokinetics to insulin transdermal injection and vaccine development over the past decade. The four hot spots in microneedle studies, including skin rejuvenation, vaccines, fabrication technology and insulin delivery, were identified. Microneedle vaccination shows promising application prospects, and polymers are considered as the most promising materials for microneedles manufacturing.ConclusionsThis study will help researchers understand the hot spots and trends of microneedles in the biomedical field accurately and quickly. Moreover, the exploitation of novel polymeric microneedles will be a solid direction for subsequent research and development of transdermal drug delivery.